In the early nineteen-sixties, a man named David Wallerstein was running a chain of movie theatres in the Midwest and wondering how to boost popcorn sales. Wallerstein had already tried matinée pricing and two-for-one specials, but to no avail.

According to Greg Critser, the author of “Fat Land” (2003), one night the answer came to him: jumbo-sized boxes. Once Wallerstein introduced the bigger boxes, popcorn sales at his theatres soared, and so did those of another high-margin item, soda.

A decade later, Wallerstein had retired from the movie business and was serving on McDonald’s board of directors when the chain confronted a similar problem. Customers were purchasing a burger and perhaps a soft drink or a bag of fries, and then leaving. How could they be persuaded to buy more?

Wallerstein’s suggestion—a bigger bag of fries—was greeted skeptically by the company’s founder, Ray Kroc. Kroc pointed out that if people wanted more fries they could always order a second bag.“But Ray,” Wallerstein is reputed to have said, “they don’t want to eat two bags—they don’t want to look like a glutton.”

Eventually, Kroc let himself be convinced; the rest, as they say, is supersizing.